1. Field of the Invention
This invention relates to a system and method for economically transferring a sterile fluid from an enclosed single source in a sterile environment to multiple recipients in successive fashion. More particularly, this invention relates to a low cost, disposable transfer system and method that allows a single reservoir to provide a relatively high flow rate of sterile fluid into several independent paths without danger of cross-contamination between any of the recipients, but with efficient use of the fluid.
2. Description of the Prior Art
Many medical and biologically compatible solutions for human and animal use are supplied in closed sterile containers having fixed volumes (e.g. 500 cc of saline or other isotonic solution). The solution is expensive because of the biologic and sterility requirements that must be met. In a typical widely used surgical procedure in opthalmology, for example, a system is employed in which the eye is irrigated and occasionally aspirated as required. Irrigation is accomplished by feeding the chosen sterile solution into the eye by an implanted or attached device at a controlled rate using a flow control device such as a drip regulating chamber. By far the most widely used system is based on the use of a sterile container having a puncturable elastomeric seal and a disposable administration set having a spike ended conduit at one end, an integral drip chamber, and a needle, catheter or other delivery device at the other end of a flexible tubing. The spike, which is sterile, is used to penetrate into the container through the seal. Since the flow rate can be substantial the size of the conduit must be of moderate size (e.g. 1/8" inner diameter) to allow for unrestricted flow under gravity feed conditions. The administration sets are commercially available products having a number of different forms. Because of cost, ease of use, and reliability this system of spiking into an elastomeric seal is used in the great majority of administration sets. Medical practitioners and hospitals maintain a large inventory of such sets and prefer to use the seal/spike approach for cost and convenience reasons.
While these types of transfer systems maintain the fluid in a sterile condition from the supply container to the individual, they are often quite costly to use because with present devices much of the solution is often wasted. Once the seal is punctured and the spike is removed the seal is no longer sterile. Of the 500 cc in a standard container, for example, only about 20-30% is typically employed in a routine cataract removal, for example. Thus, when the operation is complete, the remainder of the bottle is discarded. Furthermore, using smaller fixed volumes (e.g. 250 cc) of solutions is not cost efficient since they are disproportionately priced in comparison to the larger volumes (e.g. 500 cc), and it is not practical to carry a large inventory of different sized containers or to use very small containers in series.
There are certain known types of connector systems than can fully utilize the sterile solution of a container by enabling successive connection to different individuals. These systems employ a special manifold having multiple ports, each including a special connector and a control valve. Additional tubing sets can be attached if they have special mating connectors. However, the tubing sets then are available only for use in this type of system. Such coupling systems are impractical and too expensive for many applications, because of the cost of the special connectors and attachments.
There is an economic need to utilize all of the sterile solution which is stored in a punctured container. The desired system and method should be able to maintain a high flow rate of the solution, yet yield multiple independent pathways. The independent pathways should be designed so that when one pathway has been used it may be closed off without affecting the sterile condition of the adjacent pathways. The system and method should also allow for multiple withdrawals from the solution without a decrease in flow rate using standard sized medical attachments or the like.